In the first variation, Bb is further embellished by C5, a "one-too-far" style of expansion that should be familiar to you by now if you have followed this series of posts on van Eyck. Significantly, this gesture is repeated -- see *1 and *3 below. At *2 the C5 even reaches an accented position and acts as the upper fifth for the cadential F4.
Van Eyck might have exploited the extensions of the second variation, but in fact in the second variation he holds close to the first one. In the two boxes on the first line below, note the upper third embellishments of Bb and A, the former generating the first D5 in the set. The third box (at the end) contains the surprise: a sudden flourish carries the final cadence up to that D5, rather than down to the D4 of the tune. We should not try to interpret this as the unveiling of a rising Urlinie, but rather as a variant of the cadenza-like flourish we have already seen van Eyck employ several times in closing cadences. Here it realizes the ^7-^8 always implicit in the background of a ^2-^1 cadence, but, although the upper fourth is introduced in a dramatic fashion, the lower fifth clearly has priority.
